Focusing device in a center focusing type binocular

ABSTRACT

A center focusing type binocular having a first and a second body tube interconnected so that at least one of the body tubes is revolvable about a pivot sleeve, and inner lens frames for holding ocular systems therein and mounted for sliding along optical axes within the respective body tubes. The focusing device is improved in that the first body tube is formed with a guide groove extending axially from the end thereof adjacent to a T-shaped slidable tube, the second body tube is formed with a guide groove extending axially from the end thereof adjacent to a T-shaped rotatable ring, both grooves being parallel to the pivot sleeve, and an O-ring is interposed between each of the guide grooves and slidable shafts inserted in said grooves, whereby a perfect air-tight condition is maintained in the focusing device without using any seal means and a reduced torque is required to adjust the relative position of the two body tubes in accordance with the interpupillary distance of any viewer.

Unite States Sato [451 Jan. 23, 1973 FOCUSING DEVICE IN A CENTER PrimaryExaminer David H. Rubin FOCUSING TYPE BINOCULAR Attarney-Joseph M.Fitzpatrick et al.

[75] Inventor: Akira Sat0,Toky0,Japan [57] ABSTRACT 73 Assignee; NipponKogaku K K T k J n A center focusing type binocular having a first and ag second body tube interconnected so that at least one [22] Fil d; D 23,1971 of the body tubes is revolvable about a pivot sleeve, and innerlens frames for holding ocular systems [2]] Appl. No.: 211,378 thereinand mounted for .sliding along optical axes within the respective bodytubes. The focusing device is improved in that the first body tube isformed with a [30] Foreign Application Priority Data guide grooveextending axially from the end thereof adjacent to a T-shaped slidabletube, the second body Dec. 28, 1970 Japan ..45/l32664 tube is formedwith a guide groove extending axially 52 US. Cl ..350/76, 350/36 fmm theend there adjacent a T'Shaped ramble ring, both grooves being parallelto the pivot sleeve,

d is h "g gg gg and an O-ring is interposed between each of the guide 0grooves and slidable shafts inserted in said grooves, whereby a perfectair-tight condition is maintained in References Clted the focusingdevice without using any seal means and a reduced torque is required toadjust the relative UNITED STATES PATENTS position of the two body tubesin accordance with the 3,484,149 12/1969 Becker et al. ..350/76interpupillary distance of any viewer.

3 Claims, 4 Drawing Figures 23 O g 2| 12b H M a I m s 8 l7 l3 7 I! I L4. I I I I I6 I 1 I 1 l \l l FOCUSING DEVICEIN A CENTER FOCUSING TYPEBINOCULAR BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to binoculars, and more particularly to a focusingdevice in center focusing type binoculars.

2. Description of the Prior Art Some of the conventional binoculars areof the type in which a rotatable focusing knob centrally disposedbetween two body tubes is rotated to move the oculars in both body tubesat the same time thereby to effect focusing, and a vision adjusting ringholding one of the oculars and screwed into one of the body tubes isrotated to adjust the focal point of said one ocular and therebycompensate for any vision difference between the two eyes of a viewer.

Such conventional binoculars have been very inconvenient to operate inthat either the focusing operation or vision adjusting operation must beeffected at the center between the two body tubes and the other must beeffected in the ocular mount portion. A further disadvantage of suchbinoculars is that their oculars are often adjustable by screws so thatthey cannot be maintained sufficiently air-tight to prevent the entry ofdust and/or humidity.

A solution to these problems has been shown in U.S. Pat. No. 3,484,149,which discloses a binocular comprising focusing knobs and a rotatablevision adjusting knob all disposed between two body tubes. Thisbinocular, however, has suffered from a disadvantage that openingsformed in the pivot sleeve thereof can not be completely sealed even bythe use of seal means, and a further disadvantage that the presence ofsuch seal means greatly increases the torque required to adjust thedistance between the two oculars in accordance with the interpupilardistance of the viewer.

SUMMARY OF THE INVENTION Accordingly, I propose, by the presentinvention, to eliminate all the foregoing disadvantages existing in theconventional focusing device in a center focusing type binocular.

According to one aspect of the present invention, there is provided in acenter focusing type binocular, a focusing device in which a perfectair-tight condition may be maintained and the torque required to adjustthe distance between two body tubes of the binocular in accordance withthe interpupilar distance of any viewer is considerably reduced.

The focusing device of the present invention is incorporated in a centerfocusing type binocular which has a first body tube, a second body tubefor vision adjustment interconnected so that at least one of the bodytubes is revolvable about a pivot sleeve, and inner lens frames forholding ocular systems therein and mounted for sliding along opticalaxes within the respective body tubes. The focusing device comprises aT-shaped slidable tube fitted in the pivot sleeve and having aninternally threaded side wall portion and two axially elongated slotsformed substantially centrally of the length of the ring, whose one endis formed with a flange. A stationary main shaft is mounted within thepivot sleeve along the center axis thereof and has a pin extendingthrough the two slots and fixed to the pivot sleeve. A

rotatable focusing knob consisting of an externally threaded ring and aknob member is rotatably fitted on the stationary main shaft along onehalf of the length thereof bisected by the pin of the stationary mainshaft. The rotatable focusing knob is screwed into the T- shapedslidable ring. A T-shaped rotatable ring consist ing of a slotted flangeportion and an externally threaded portion is rotatably and slidablyfitted on the stationary main shaft along the other half of the lengththereof bisected by the pin of the stationary main shaft. The T-shapedrotatable ring is screwed into the internally threaded portion of theT-shaped slidable ring. A rotatable vision adjusting knob consisting ofa pin extending through the slot in the flange of the T-shaped rotatablering and a knob member is rotatably mounted at the end of the stationarymain shaft which is remote from the focusing knob.

The first body tube is formed with a guide groove extending axially fromthe end thereof adjacent to the T- shaped slidable ring. The second bodytube is formed with a guide groove extending axially from the endthereof adjacent to the T-shaped rotatable ring. The guide grooves areparallel to the pivot sleeve. A slidable shaft is inserted into each ofthe grooves. An O-ring is interposed between each of the guide groovesand each of the slidable shafts and adjacent to the opposite ends of thefirst and second body tubes. The slidable shaft which is adjacent to thesecond body tube is formed with a circumferentially extending recess atone end thereof, the recess loosely receiving therein the flange of theT-shaped rotatable ring. The slidable shaft which is adjacent to thefirst body tube has one end thereof fixed to the T-shaped slidable ring;and a connecting arm is provided between each of the slidable shafts andeach of the inner lens frames.

There has thus been outlined rather broadly the more important featuresof the invention in order that the detailed description thereof thatfollows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject of the claims appended hereto. Thoseskilled in the art will appreciate that the conception upon which thisdisclosure is based may readily be utilized as a basis for the designingof other structures for carrying out the several purposes of theinvention. It is important, therefore, that the claims be regarded asincluding such equivalent construction as do not depart from the spiritand scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS A specific embodiment of the inventionhas been chosen for purposes of illustration and description, and isshown in the accompanying drawings, forming a part of the specification,wherein:

FIG. 1 is a fragmentary view, in longitudinal section, of the binocularaccording to U.S. Pat. No. 3,484,149 which is referred to for comparisonwith the present invention;

FIG. 2 is a longitudinal section of the binocular according to anembodiment of the present invention;

FIG. 3 is a sectional view taken along line A-A of FIG. 2; and

FIG. 4 is a sectional view taken along line B--B of FIG. 2. I

DESCRIPTION OF THE PREFERRED EMBODIMENT In order to make the presentinvention better understood, the binocular disclosed in U.S. Pat. No.3,484,149 will be considered with reference to FIG. 1. Members 41 and 42are respectively connected to two inner lenses (not shown). A knob 43may be rotated to move the two inner lenses in the same direction andfocus these lenses, while another knob 44 may be rotated to move one ofthe inner lenses and focus said one lens alone, thereby compensating forany vision difference between viewers two eyes. In this binocular,openings 50 and 51 are formed between body tubes 45, 46 and a pivotsleeve 47 so that pins 48 and 49 are reciprocally movable in theseopenings. The openings 50 and 51 are sealed by means of seal members 52,53 and 54. This arrangement is disadvantageous in that the seal membersfail to maintain complete air-tight integrity and that the presence ofsuch seal members 52 and 53 requires a greater torque to be applied whenthe viewer adjusts the binocular to this interpupilar distance.

Referring not to FIGS. 2, 3 and 4, there is shown an embodiment of thepresent invention wherein a first body tube 1 and a second body tube 2are interconnected by a pivot sleeve 3 and pins 4 in such a manner thatone of the two body tubes can revolve about the pivot sleeve 3. Thepivot sleeve 3 has an anti-slip nut 7 screwed thereto (FIGS. 2 and 4),which nut 7 also provides a stopper (i.e., cut-away 6 in FIG. 4) for apin which will be described. The first body tube 1 is formed with agroove 8 extending axially from one end thereof and parallel to thepivot sleeve 3, and a guide bushing 8' is bonded to the wall of thegroove 8. The groove 8 and guide bushing 8' together constitute a guidegroove. Similarly, the second body tube 2 is formed with a grooveextending axially from one end thereof and parallel to the pivot sleeve3, and a guide bushing 9 is bonded to the wall of the groove 9 togetherconstituting another guide groove. Shafts 10 and 11 are slidablyreceived in the respective guide grooves and seal members such asO-rings 12a and 12b are interposed between the respective guide bushings9, 9' and the respective slidable shafts 10, 11. A connecting shaft 13has one end secured to the slidable shaft 10 and the other end securedto a connecting arm frame 14, which in turn is secured to an ocularframe 15 by means of a threaded ring 16. The ocular frame 15 holds anocular system 17 therewithin, and the connecting arm frame 14, togetherwith the ocular frame 15, is slidable along the inner side wall of anocular casing 18 which forms a part of the first body tube 1. Theconnecting shaft 13 and the connecting arm frame 14 together constitutea connecting arm, and it will be appreciated that the slidable shaft 10,connecting arm 13-14 and ocular frame 15 are all movable together.

Similarly, a connecting shaft 19 has one end secured to the slidableshaft 11 and the other end secured to a connecting arm frame 20, whichin turn is secured to an ocular frame 21 by means of a threaded ring 22.The ocular frame 21 holds an ocular system 23 therewithin, and theconnecting arm frame 20, together with the ocular frame 21, is slidablealong the inner side wall of an ocular casing 24 which forms a part ofthe second body tube 2. The connecting shaft 19 and the connecting armframe together constitute a connecting arm.

Thus, the slidable shaft 11, connecting arm 19-20 and ocular frame 21are all movable together.

A slidable tube or ring 26, T-shaped in profile, is fitted in the pivotsleeve 3, which ring 26 has an internally threaded inner side wallportion and two axially elongated slots 25 formed through the side wallsubstantially at the center of its length, as shown in FIG. 3. One endof the tube 26 is formed with a flange portion, which is secured to theslidable shaft 10 by means of a screw 29. Thus, the T-shaped slidablering 26, slidable shaft 10, connecting arm 13-14 and ocular frame 15 areall movable together. A stationary main shaft 28 extends axially throughthe T-shaped slidable tube 26 and has a pin 27 passing through the twoslots 25 in the tube 26 and secured to the pivot sleeve 3. A ring 30having an externally threaded portion is screwed into the T- shapedslidable tube 26 for rotation relative to the stationary main shaft 28.A rotatable knob member 33 is secured to the threaded ring 30 by meansof screws 32 so that the knob member 33 and ring 30 together constitutea rotatable focusing knob, which is retained against axial=slidingmotion by a projection 28' formed on the stationary main shaft 28 and ascrew 34 fixing the knob to the main shaft.

At that end of the T-shaped slidable tube 26 which is remote from itsflanged end, a T-shaped rotatable ring 31 is fitted in the tube 26 forrotation and axial sliding relative to the stationary main shaft 28. TheT-shaped rotatable ring 31 includes an externally threaded portion and aflanged portion formed with an oval slot 39, as shown in FIG. 4. Theflange of the T-shaped rotatable ring 31 is loosely received in a recess11' formed circumferentially of the slidable shaft 11 at the adjacentend thereof. A disc 35, secured to the main shaft 28 has a rotatableknob member 36 secured thereto by means of pins 37, and also carries thepin 5 which extends through the oval slot 39 so as to engage the cutaway6 of the nut 7. The disc 35 and rotatable knob member 36 togetherconstitute a rotatable vision adjusting knob, which is retained againstaxial movement by a screw 38 attaching it to the stationary main shaft28, for rotation relative thereto.

Description will now be made of the process for driving the respectivefocusing mechanisms in the abovedescribed binocular.

A focusing operation may be achieved by rotating the focusing knobmember 33. More specifically, when the threaded ring 30 is rotated withthe rotation of the knob member 33, the T-shaped slidable tube 26 iscaused to slide axially with the aid of the pin 27 guided in the slot25, so that the slidable shaft 10, the connecting shaft 13, theconnecting arm frame 14 and the ocular system 17 held by and within theocular frame 15 are all displaced axially. At the same time, the T-shaped rotatable ring 31 is rotated since the thread on this ring are inmesh with the threads on the T-shaped slidable tube 26, whereby the ring31, having its flange engaged with the recess 11', causes the slidableshaft 11, connecting shaft 19, connecting arm frame 20 and ocular system23 held by and within the ocular frame 21 all to be axially displaced inthe same direction and over the same distance as the aforesaiddisplacement of the first ocular system 17 and its corresponding parts.

Adjustment for the correction of the vision difference between the twoeyes of a viewer may be achieved by rotating the rotatable visionadjusting knob member 36. In this case, the flange of the T-shapedrotatable ring 31 is rotated by the pin 5 and slides in the recess 11'of the slidable shaft 11 to thereby displace the slidable shaft 11 inits axial direction. It will be seen that during this adjustment, theT-shaped slidable tube 26 remains stationary so that the ocular system23 alone is axially displaced to correct and compensate for visiondifference between the eyes.

Although the above-described embodiment is constructed such thatrotation of the rotatable focusing knob and rotatable vision adjustingknob causes displacement of the oculars, it is of course possible toadopt such a construction that rotation of those knobs causesdisplacement of objectives or prisms depending on the type of theoptical systems used.

According to the present invention, as has been noted above, the guidegrooves 8 and 9 are the only openings formed in the body tubes and thesegrooves can be maintained perfectly air-tight because of the 0' ringsinterposed between the respective guide grooves and the slidable shaft.This completely prevents any clouding in the interior of the binocular,and the absence of any seal member between the body tubes and the pivotsleeve ensures smooth adjustment of the distance between the two bodytubes in accordance with the interpupilar distance of the viewer.Additionally, as has been noted, the torque required for adjustment ofthe body tubes to suit the interpupilar distance of the viewer isconsiderably reduced.

I believe that the construction and operation of my novel centerfocusing binocular will be understood, and that its advantages will befully appreciated by those persons skilled in the art.

lclaim:

1. A focusing device in a center focusing type binocular having a firstbody tube and a second body tube for vision adjustment interconnected sothat at least one of the body tubes is pivotable about an axis betweenthe tubes, and lens frames holding ocular systems and mounted forsliding along optical axes within the respective body tubes, saidfocusing device comprising:

a stationary main shaft the central axis of which is coincident with thepivot axis between said tubes;

rotatable focusing means including an externally threaded ring and aknob member, said focusing means being rotatably fitted on saidstationary main shaft along a portion of its length;

tube means having internal threads in mesh with the externally, threadedring of said focusing means, said tube means having axially elongatedslots formed substantially centrally of its length, and a flange at one.end thereof;

a pivot sleeve positioned around said tube means;

a pin extending laterally through said main shaft and through said slotsin said tube means and secured to said pivot sleeve;

ring means including a slotted flange and an externally threaded shankportion, said ring means being rotatably and slidably fitted on saidstationary main shaft along the other portion of its length, said ringmeans being screwed into the internally threaded portion of said tubemeans;

an ocular system in each of said body tubes and shiftable longitudinallyrelatively to said main shaft upon rotation of said focusing knob; and

means connecting one ocular system with said tube means and the otherocular system with-said ring means for shifting said ocular systems uponrotation of said focusing knob.

2. A focusing device according to claim 1, wherein a vision adjustingknob is rotatably mounted at the end of said main shaft remote from saidfocusing knob and includes a pin extending through the slot in said ringmeans and a knob member, whereby rotation of said knob member and pineffects rotation of said ring means and independent longitudinalshifting of the respective connecting means and said other ocular systemin one of said body tubes to correct for the vision difference betweenthe eyes of a viewer.

3. A focusing device in a center focusing type binocular having a firstbody tube and a second body tube for vision adjustment interconnected sothat at least one of the body tubes is pivotable about an axis betweenthe tubes, and lens frames holding ocular systems and mounted forsliding along optical axes within the respective body tubes, saidfocusing device comprising:

a stationary main shaft the central axis of which is coincident with thepivot axis between said tubes;

rotatable focusing means including an externally threaded ring and aknob member, said focusing means being rotatably fitted on saidstationary main shaft along a portion of its length;

tube means having internal threads in mesh with the externally threadedring of said focusing means, said tube means having axially elongatedslots formed substantially centrally of its length, and a flange at oneend thereof;

a pivot sleeve positioned around said tube means;

a pin extending laterally through said main shaft and through said slotsin said tube means and secured to said pivot sleeve;

ring means including a slotted flange and an externally threaded shankportion, said ring means being rotatably and slidably fitted on saidstationary main shaft along the other portion of its length, said ringmeans being screwed into the internally threaded portion of said tubemeans;

a vision adjusting knob rotatably mounted at the end of said main shaftremote from said focusing means, said vision adjusting knob including apin extending through the slot in said flange of said ring means and aknob member;

said first body tube being formed with a guide groove extending axiallyfrom the end thereof adjacent to said tube means, said second body tubebeing formed with a guide groove extending axially from the end thereofadjacent to said ring means, both of said guide grooves being parallelto said pivot sleeve;

a slidable shaft inserted into each of said grooves;

sealing means interposed between each of said guide grooves and each ofsaid slidable shafts and adjacent to the opposite ends of said first andsecond body tubes;

said slidable shaft adjacent to said second body tube being formed witha circumferentially extending recess at one end thereof, said recessloosely receiving therein said flange of said ring means; said slidableshaft adjacent to said first body tube having one end thereof fixed tosaid tube means; and connected means provided between each of saidslidable shafts and one of said inner lens frames.

1. A focusing device in a center focusing type binocular having a firstbody tube and a second body tube for vision adjustment interconnected sothat at least one of the body tubes is pivotable about an axis betweenthe tubes, and lens frames holding ocular systems and mounted forsliding along optical axes within the respective body tubes, saidfocusing device comprising: a stationary main shaft the central axis ofwhich is coincident with the pivot axis between said tubes; rotatablefocusing means including an externally threaded ring and a knob member,said focusing means being rotatably fitted on said stationary main shaftalong a portion of its length; tube means having internal threads inmesh with the externally threaded ring of said focusing means, said tubemeans having axially elongated slots formed substantially centrally ofits length, and a flange at one end thereof; a pivot sleeve positionedaround said tube means; a pin extending laterally through said mainshaft and through said slots in said tube means and secured to saidpivot sleeve; ring means including a slotted flange and an externallythreaded shank portion, said ring means being rotatably and slidablyfitted on said stationary main shaft along the other portion of itslength, said ring means being screwed into the internally threadedportion of said tube means; an ocular system in each of said body tubesand shiftable longitudinally relatively to said main shaft upon rotationof said focusing knob; and means connecting one ocular system with saidtube means and the other ocular system with said ring means for shiftingsaid ocular systems upon rotation of said focusing knob.
 2. A focusingdevice according to claim 1, wherein a vision adjusting knob isrotatably mounted at the end of said main shaft remote from saidfocusing knob and includes a pin extending through the slot in said ringmeans and a knob member, whereby rotation of said knob member and pineffects rotation of said ring means and independent longitudinalshifting of the respective connecting means and said other ocular systemin one of said body tubes to correct for the vision difference betweenthe eyes of a viewer.
 3. A focusing device in a center focusing typebinocular having a first body tube and a second body tube for visionadjustment interconnected so that at least one of the body tubes ispivotable about an axis between the tubes, and lens frames holdingocular systems and mounted for sliding along optical axes within therespective body tubes, said focusing device comprising: a stationarymain shaft the central axis of which is coincident with the pivot axisbetween said tubes; rotatable focusing means including an externallythreaded ring and a knob member, said focusing means being rotatablyfitted on said stationary main shaft along a portion of its length; tubemeans having internal threads in mesh with the externally threaded ringof said focusing means, said tube means having axially elongated slotsformed substantially centrally of its length, and a flange at one endthereof; a pivot sleeve positioned around said tube means; a pinextending laterally through said main shaft and through said slots insaid tube means and secured to said pivot sleeve; ring means including aslotted flange and an exterNally threaded shank portion, said ring meansbeing rotatably and slidably fitted on said stationary main shaft alongthe other portion of its length, said ring means being screwed into theinternally threaded portion of said tube means; a vision adjusting knobrotatably mounted at the end of said main shaft remote from saidfocusing means, said vision adjusting knob including a pin extendingthrough the slot in said flange of said ring means and a knob member;said first body tube being formed with a guide groove extending axiallyfrom the end thereof adjacent to said tube means, said second body tubebeing formed with a guide groove extending axially from the end thereofadjacent to said ring means, both of said guide grooves being parallelto said pivot sleeve; a slidable shaft inserted into each of saidgrooves; sealing means interposed between each of said guide grooves andeach of said slidable shafts and adjacent to the opposite ends of saidfirst and second body tubes; said slidable shaft adjacent to said secondbody tube being formed with a circumferentially extending recess at oneend thereof, said recess loosely receiving therein said flange of saidring means; said slidable shaft adjacent to said first body tube havingone end thereof fixed to said tube means; and connected means providedbetween each of said slidable shafts and one of said inner lens frames.